Cooling apparatus and method for cooling a continuous strip

ABSTRACT

The invention relates to a cooling apparatus and a method for cooling a continuous strip, wherein the cooling apparatus comprises a cooling drum and a guiding device for guiding the strip in a plurality of windings around the cooling drum, wherein the guiding device comprises first and second guiding elements, wherein each one of the first guiding elements forms a set with one of the second guiding elements, wherein the first guiding element of the set receives the strip from a first winding in a first winding direction and directs the strip in a first transition direction towards the second guiding element which receives the strip in a second transition direction and directs the strip into a consecutive winding in a second winding direction, wherein the first transition direction is different from the first winding direction and the second transition direction is different from the second winding direction.

BACKGROUND

The invention relates to a cooling apparatus and a method for cooling acontinuous strip.

FIG. 13 shows a prior art cooling apparatus used to cool a freshlyextruded continuous strip, in particular an apex or a bead filler foruse in tire building. The known cooling apparatus comprises a coolingdrum with a circumferential cooling surface for receiving a plurality ofwindings of the continuous strip and a set of crowned steering rollersarranged coaxially at the top of the cooling apparatus above saidcooling drum. The continuous strip is guided from the cooling surfaceover one of the steering rollers and back onto the cooling surface witheach winding. The set of steering rollers is arranged to be placed at anadjustable angle to the rotation axis of the cooling drum to set thepitch of the windings.

SUMMARY OF THE INVENTION

A disadvantage of the known cooling apparatus is that the steeringrollers are increasingly offset relative to the surface of the coolingdrum. As the distance between the point where the continuous stripleaves the cooling surface and where it runs over a respective one ofthe steering rollers can vary considerably, the distance over which thecontinuous strip is unguided is also considerable. Consequently, thecontinuous strip may behave differently and unpredictably during thewinding. In particular, the steering rollers may pull on the continuousstrip in the axial direction while said continuous strip is stillsupported on the cooling surface, causing the continuous strip to slideand/or deform unpredictably. Moreover, the continuous strip slowlystiffens as it cools down during its stay on the cooling drum. Thecontinuous strip therefore behaves differently when winding over thelater steering rollers with respect to the windings over the earliersteering rollers. In some cases, the continuous strip may run off to theside uncontrollably and stick to adjacent windings.

It is an object of the present invention to provide a cooling apparatusand a method for cooling a continuous strip, wherein the winding can bemore accurately controlled.

According to a first aspect, the invention provides a cooling apparatusfor cooling a continuous strip, wherein the cooling apparatus comprisesa cooling drum with a cylindrical cooling surface that extends in acircumferential direction and has a rotation axis concentric to thecooling surface and extending in an axial direction, wherein the coolingapparatus further comprises a guiding device for guiding the continuousstrip in a plurality of windings around the cooling surface, wherein theguiding device comprises first guiding elements and second guidingelements, wherein each one of the first guiding elements forms a setwith one of the second guiding elements to guide the continuous strip ina transition from a first winding to a consecutive winding of theplurality of windings, wherein the first guiding element of the set isarranged for receiving the continuous strip from the first winding in afirst winding direction and for directing the continuous strip in afirst transition direction, wherein the second guiding element of theset is arranged for receiving the continuous strip in a secondtransition direction and for directing the continuous strip into theconsecutive winding in a second winding direction, wherein the firsttransition direction is different from the first winding direction andthe second transition direction is different from the second windingdirection.

Hence, the continuous strip can be directed from the first winding intothe consecutive winding between the first guiding element and the secondguiding element of the set in a controlled manner. Moreover, it can beprevented that the change in direction of the continuous strip betweenthe first guiding element and the second guiding element of the setnegatively affects the continuous strip upstream of the first guidingelement and downstream of the second guiding element. In particular, thefirst guiding element allows for a precise receiving of the continuousstrip from the cooling drum and the second guiding element allows for aprecise placement of the continuous strip back onto the cooling drum.The continuous strip can be directed directly from the first guidingelement to the second guiding element or indirectly via one or morefurther guiding element of the set to the second guiding element.

In a preferred embodiment, the first guiding element of the set isarranged for directing the continuous strip in the first transitiondirection towards the second guiding element of the set and wherein thesecond guiding element of the set is arranged for receiving thecontinuous strip from the first guiding element of the set in the secondtransition direction, wherein the second transition direction is thefirst transition direction. Hence, the second guiding element canreceive the continuous strip from the first guiding element in the samedirection that was given to the continuous strip at said first guidingelement.

Alternatively, the guiding device comprises one or more third guidingelements between the first guiding element and the second guidingelement of each set, wherein the one or more third guiding elements arearranged for receiving the continuous strip in the first transitiondirection from the first guiding element and for directing thecontinuous strip towards the second guiding element in the secondtransition direction. Hence, the second guiding element can receive thecontinuous strip from the first guiding element in a slightly differentdirection than the direction that was given to the continuous strip atsaid first guiding element. In particular, because of the presence ofthe third guiding element, the twist or deflection of the continuousstrip at the first guiding element and/or the second guiding element canbe slightly reduced to prevent axial shifting or shear deformation.

In an embodiment the continuous strip has a longitudinal direction,wherein the first guiding elements and the second guiding elements arearranged for twisting the continuous strip about the longitudinaldirection thereof prior to directing the continuous strip from the firstwinding direction into the first transition direction and from thesecond transition direction into the second winding direction. Bytwisting the continuous strip prior to changing its direction, thecontinuous strip can be placed in an optimal orientation for thesubsequent deflection of said continuous strip from the first windingdirection into the first transition direction and from the secondtransition direction into the second winding direction.

In a further embodiment the first winding direction and the secondwinding direction are tangent to the cooling surface. Hence, thecontinuous strip can be received from the cooling surface along astraight line and placed back onto the cooling surface along a straightline.

In a preferred embodiment thereof the first guiding elements are at afirst distance from the cooling surface in the first winding direction,wherein the first distance is the same or substantially the same for allfirst guiding elements. Additionally, or alternatively, the secondguiding elements are at a second distance from the cooling surface inthe second winding direction, wherein the second distance is the same orsubstantially the same for all second guiding elements. By keeping thedistances the same, the behavior of the continuous strip can be keptsubstantially the same for each winding.

In a further embodiment the first winding direction extends in a firstwinding plane and the second winding direction extends in a secondwinding plane parallel to yet spaced apart from the first winding plane.The continuous strip can thus be received at the first guiding elementin the same winding plane in which the first winding extends and can beplaced back onto the cooling drum while already extending in the secondwinding plane.

In a preferred embodiment thereof the first winding plane and the secondwinding plane extend perpendicular to the rotation axis. Consequently,the continuous strip can be wound around the cooling drum in ‘straight’windings, meaning that each winding extends in a single plane, whereinthe continuous strip is transitioned from the first winding plane to thesecond winding plane between the first guiding element and the secondguiding element only. Hence, the continuous strip can be wound neutrallyor substantially neutrally about the cooling drum.

In a further embodiment the second guiding element of the set is offsetwith respect to the first guiding element of the set in the axialdirection. As a result, the continuous strip can be transported from thefirst winding to the consecutive winding when moving from the firstguiding element to the second guiding element.

In a further embodiment the second guiding element of the set is offsetwith respect to the first guiding element of the set in thecircumferential direction. By offsetting the guiding elements in thecircumferential direction, the change in direction of the continuousstrip can be made less abrupt.

In a preferred embodiment thereof the first guiding element and thesecond guiding element of the set are spaced apart in thecircumferential direction over a spacing angle in the range of twenty tosixty degrees, preferably thirty to forty degrees. At such spacingangle, the continuous strip can be made to transition gradually, whilethe continuous strip is still in contact with the cooling surface duringa sufficient part of the remaining circumference.

In a further embodiment thereof the first guiding element and the secondguiding element of the set define a linear transition path for thecontinuous strip, wherein the first guiding element and the secondguiding element of the set are positioned relative to the coolingsurface so that the transition path is completely spaced apart from thecooling surface. The transition can thus take place completelyindependently from the cooling surface. In particular, deformation as aresult of sliding contact of the continuous strip with the coolingsurface during the transition can be prevented.

In a further embodiment the second guiding element of the set is alignedin the circumferential direction with the first guiding element of aconsecutive one of the sets. Once the continuous strip is in the secondwinding direction, the continuous strip can already be effectivelyaligned with the first guiding element, thus requiring no substantialaxial shifting of the continuous strip while said continuous strip issupported on the cooling drum.

In a further embodiment the first guiding element and the second guidingelement of the set are arranged for deflecting the continuous stripabout a first deflection axis and a second deflection axis,respectively, wherein the first deflection axis is tilted at an obliquefirst angle to the rotation axis and wherein the second deflection axisis tilted at an oblique second angle to the rotation axis, opposite tothe first angle. By tilting the deflection axes as specified, thecontinuous strip can be twisted about its longitudinal axis. Thedirection of the twist positions the continuous strip optimally fordeflection from the first winding direction into the first transitiondirection, so that the continuous strip may be merely deflected, i.e. apure deflection without any substantial axial shifting or sheardeformation.

Additionally, or alternatively, the first deflection axis isperpendicular to the first winding direction and the first transitiondirection and/or the second deflection axis is perpendicular to thesecond winding direction and the second transition direction. Hence thecontinuous strip may be merely deflected in a direction perpendicular tothe respective first winding direction, the second winding direction,the first transition direction and the second transition direction. Theresult can be a pure deflection without any substantial axial shiftingor shear deformation

In a preferred embodiment thereof the first guiding element and thesecond guiding element of the set are a first guiding roller and asecond guiding roller, respectively, wherein the first deflection axisand the second deflection axis correspond to the axes of the firstguiding roller and the second guiding roller, respectively. The guidingrollers can effectively guide and deflect the continuous strip about thedeflection axes while conveying the continuous strip with minimalfriction. Alternatively, stationary and/or non-rotatable guidingelements having a suitable sliding surface may be used.

In a further embodiment the first guiding elements are arrangedside-by-side in the axial direction. Hence, the first guiding elementscan be arranged in a simple array, i.e. on a common support relative tothe cooling drum.

In another embodiment the second guiding elements are arrangedside-by-side in the axial direction. Hence, the second guiding elementscan be arranged in a simple array, i.e. on a common support relative tothe cooling drum.

In a further embodiment the cooling apparatus comprises a base forrotatably supporting the cooling drum about the rotation axis, whereinthe guiding device is supported relative to said base in a stationaryangular position about the rotation axis. The continuous strip can thusbe transition from after each winding in substantially the same angularposition, thereby increasing the consistency of said transitions acrossthe continuous strip, regardless of the progress of the curing.

In a preferred embodiment thereof, the angular position is at astationary angle within a range of zero to sixty degrees with respect tothe horizontal plane. Within said range, the guiding device can beeasily reached by an operator. In contrast, the prior art steeringrollers are arranged at the top of the cooling drum.

In a further embodiment the guiding device further comprises one or morefirst alignment elements for aligning the continuous strip at one ormore of the first guiding elements along an entry line. By aligning thecontinuous strip, the continuous strip can be positioned accuratelyprior to the transition.

In a preferred embodiment thereof the one or more first aligningelements are one or more first alignment rollers, wherein each of theone or more first alignment rollers is arranged alongside one of thefirst guiding elements for abutting the continuous strip in the axialdirection at the entry line. The rollers can effectively align thecontinuous strip while simultaneously conveying the continuous stripwith minimal friction.

In a further embodiment thereof, the continuous strip has an insidefacing towards the cooling drum, wherein said one or more firstalignment rollers are arranged for obliquely abutting the inside of thecontinuous strip at the entry line. By obliquely abutting the inside ofthe continuous strip, unintentional deformations at the side (the baseor the tip) of the strip can be prevented.

In a further embodiment the guiding device further comprises one or moresecond alignment elements for aligning the continuous strip at one ormore of the second guiding elements along an exit line. The secondalignment elements can effectively align the continuous strip for moreaccurate placement of said strip back onto the cooling drum.

In a preferred embodiment thereof the one or more second aligningelements are one or more first alignment rollers, wherein each of theone or more second alignment rollers is arranged alongside one of thesecond guiding elements for abutting the continuous strip in the axialdirection at the exit line. The rollers can effectively align thecontinuous strip while simultaneously conveying the continuous stripwith minimal friction.

In a further preferred embodiment thereof, the continuous strip has aninside facing towards the cooling drum, wherein said one or more secondalignment rollers are arranged for obliquely abutting the inside of thecontinuous strip at the exit line. By obliquely abutting the inside ofthe continuous strip, unintentional deformations at the side (the baseor the tip) of the strip can be prevented.

In an alternative embodiment the first guiding element and the secondguiding element of the set define a transition path for the continuousstrip, wherein the guiding device further comprises one or morealignment elements at an intermediate position along the transition pathbetween the first guiding element and the second guiding element of eachset for steering the continuous strip along the respective transitionpath. The one or more alignment elements can effectively correctdeviations of the continuous strip from the transition path.

In a preferred embodiment thereof the one or more alignment elementscomprises a first alignment roller and a second alignment roller whichare oppositely inclined. The rollers can effectively align thecontinuous strip while simultaneously conveying the continuous stripwith minimal friction. The opposite inclination means that the rollerscan abut the continuous strips from opposite or different sides.

In a further alternative embodiment the plurality of windings comprisesan infeed winding where the continuous strip is first applied to thecooling drum, wherein the cooling apparatus comprises an infeed pullingmember for feeding the continuous strip into the infeed winding at aninfeed speed, wherein the cooling apparatus further comprises a controlunit that is operationally connected to the cooling drum to control therotational speed of said cooling drum, wherein the control unit isoperationally connected to the infeed pulling member and configured tocontrol the infeed pulling member such that the infeed speed is lowerthan the rotational speed of the cooling drum. The continuous strip,which is still warm and flexible during the infeed winding, can beslightly pulled back to reduce or prevent sagging or slacking. Inparticular, the slight pull back on the continuous strip can ensure thatthe infeed winding is tightly wound around the cooling drum, therebyimproving the effectiveness of said cooling drum.

It is noted that the infeed pulling member can be applied with a coolingdrum both in combination and independently of the previously discussedguiding device.

In a preferred embodiment thereof the plurality of windings comprises anoutfeed winding where the continuous strip ultimately leaves the coolingdrum, wherein the cooling apparatus further comprises an outfeed pullingmember for feeding the continuous strip out of the outfeed winding awayfrom the cooling drum, wherein the control unit is operationallyconnected to the outfeed pulling member and configured to control theoutfeed pulling member such that it pulls on the continuous strip at anoutfeed rate that is higher than the rotational speed of the coolingdrum. At the outfeed winding, the continuous strip may already bepartially cooled and relatively inflexible. By pulling the continuousstrip forward out of outfeed winding, it can be prevented that thecontinuous strip leaves the outfeed winding unintentionally.

It is noted that the outfeed pulling member can be applied with acooling drum both in combination and independently of the previouslydiscussed guiding device.

According to a second aspect, the invention provides a production linefor producing a continuous strip, wherein the production line comprisesan extruder for extruding the continuous strip at a variable extrusionspeed, a cooling apparatus similar to the cooling apparatus according toany one of the preceding embodiments for cooling the continuous stripand a buffer member between the extruder and the cooling apparatus toabsorb variations in the extrusion speed, wherein the plurality ofwindings comprises an infeed winding where the continuous strip is firstapplied to the cooling drum, wherein the cooling apparatus comprises aninfeed pulling member that is located between the buffer member and thecooling drum for feeding the continuous strip into the infeed winding atan infeed speed, wherein the production line further comprises a controlunit that is operationally connected to the cooling drum to control therotational speed of said cooling drum, wherein the control unit isoperationally connected to the infeed pulling member and configured tocontrol the infeed pulling member such that the infeed speed is lowerthan the rotational speed of the cooling drum.

The production line comprises the cooling apparatus according to any oneof the preceding embodiments and thus has the same technical advantagesSaid technical advantages will not be repeated hereafter.

In a preferred embodiment of the production line the plurality ofwindings comprises an outfeed winding where the continuous stripultimately leaves the cooling drum, wherein the cooling apparatusfurther comprises an outfeed pulling member for feeding the continuousstrip out of the outfeed winding away from the cooling drum, wherein thecontrol unit is operationally connected to the outfeed pulling memberand configured to control the outfeed pulling member such that it pullson the continuous strip at an outfeed rate that is higher than therotational speed of the cooling drum.

According to a third aspect, the invention provides a method for coolinga continuous strip using the cooling apparatus according to any one ofthe previously discussed embodiments, wherein the method comprises thesteps of:

-   receiving the continuous strip from the first winding at the first    guiding element of the set in the first winding direction;-   directing the continuous strip in the first transition direction;-   receiving the continuous strip at the second guiding element of the    set in the second transition direction; and-   directing the continuous strip into the consecutive winding in the    second winding direction.

In a preferred embodiment the continuous strip is directed in the firsttransition direction towards the second guiding element of the set andreceived at the second guiding element from the first guiding element ofthe set in the second transition direction, wherein the secondtransition direction is the first transition direction.

Alternatively, the guiding device comprises one or more third guidingelements between the first guiding element and the second guidingelement of each set, wherein the method further comprises the steps ofreceiving the continuous strip in the first transition direction at oneor more third guiding elements from the first guiding element anddirecting the continuous strip towards the second guiding element in thesecond transition direction.

In a further embodiment thereof the continuous strip has a longitudinaldirection, wherein the method further comprises the steps of:

-   twisting the continuous strip about the longitudinal direction prior    to directing the continuous strip from the first winding direction    into the first transition direction; and-   twisting the continuous strip about the longitudinal direction prior    to directing the continuous strip from the second transition    direction into the second winding direction.

The method relates to the practical implementation of the coolingapparatus. Therefore, the method and its embodiments have the sametechnical advantages as the cooling apparatus and its correspondingembodiments. Said technical advantages will not be repeated hereafter.

In another embodiment the method further comprises the steps of aligningthe continuous strip at one or more of the first guiding elements alongan entry line.

In a further embodiment the method further comprises the steps ofaligning the continuous strip at one or more of the second guidingelements along an exit line.

In a further embodiment the plurality of windings comprises an infeedwinding where the continuous strip is first applied to the cooling drum,wherein the method further comprises the step of:

winding the infeed winding over at least a quarter up to at least threequarters of the circumference of the cooling surface in thecircumferential direction prior to receiving the continuous strip at thefirst of the first guiding elements. By increasing the length of theinfeed winding, the effectiveness of the cooling drum can be improved.

In a further embodiment the plurality of windings comprises an outfeedwinding where the continuous strip ultimately leaves the cooling drum,wherein the method further comprises the step of:

winding the outfeed winding over at least a quarter up to at least threequarters of the circumference of the cooling surface in thecircumferential direction after the continuous strip has left the lastof the second guiding elements. By increasing the length of the outfeedwinding, the effectiveness of the cooling drum can be improved.

In a further embodiment of the method the plurality of windingscomprises an infeed winding where the continuous strip is first appliedto the cooling drum, wherein the method comprises the step of feedingthe continuous strip into the infeed winding at an infeed speed that islower than the rotational speed of the cooling drum.

In a further embodiment thereof the plurality of windings comprises anoutfeed winding where the continuous strip ultimately leaves the coolingdrum, wherein the method further comprises the step of pulling on thecontinuous strip that leaves the outfeed winding at an outfeed speedthat is higher than the rotational speed of the cooling drum.

The various aspects and features described and shown in thespecification can be applied, individually, wherever possible. Theseindividual aspects, in particular the aspects and features described inthe attached dependent claims, can be made subject of divisional patentapplications.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be elucidated on the basis of an exemplary embodimentshown in the attached schematic drawings, in which:

FIG. 1 shows an isometric view of a cooling apparatus with a coolingdrum and a guiding device according to a first embodiment of theinvention for guiding a continuous strip in a plurality of windingsaround the cooling drum;

FIG. 2 shows a front view of the cooling apparatus according to FIG. 1 ;

FIG. 3 shows a side view of the cooling apparatus according to FIG. 1 ;

FIG. 4 shows an isometric view of a detail of the guiding deviceaccording to FIG. 1 ;

FIG. 5 an isometric view from an opposite side of the detail of theguiding device according to FIG. 4 ;

FIG. 6 shows a front view of the detail of the guiding device accordingto FIG. 4 ;

FIG. 7 shows a top view of the detail of the guiding device according toFIG. 4 ;

FIGS. 8A and 8B show a front view and a side view, respectively, of atwo-dimensional rollout of the cylindrical cooling surface of thecooling drum;

FIGS. 9A and 9B show a first winding and a last winding, respectively,of a plurality of windings of the continuous strip around the coolingdrum;

FIG. 10 shows a detail of an alternative cooling apparatus according toa second embodiment of the invention;

FIGS. 11A and 11B show a production line with a further alternativecooling apparatus according to a third embodiment of the invention,while feeding in or feeding out the first winding and the last winding,respectively;

FIG. 12 shows a further alternative cooling apparatus according to afourth embodiment of the invention; and

FIG. 13 shows a prior art cooling apparatus.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1, 2 and 3 show a cooling apparatus 1 for cooling a continuousstrip 9 according to a first exemplary embodiment of the invention. Thecontinuous strip 9 extends in or has a longitudinal direction L. In thisexemplary embodiment, said continuous strip 9 is a freshly extruded apexor bead filler for use in tire building. Said apex or bead filler has atriangular cross section, best seen in FIG. 2 , having an inside surface90, a base 91 and a tip 92.

The cooling apparatus 1 comprises a cooling drum 2 and a base 3 forsupporting said cooling drum 2 relative to a ground surface, e.g. afactory floor. The cooling drum 2 has a cylindrical cooling surface 20extending in a circumferential direction D about a rotation axis Sconcentric to the cooling surface 20. The rotation axis S extends in ordefines an axial direction X. The cooling drum 2 is rotatably supportedon or relative to said base 3 so as to be rotatable about the rotationaxis S. The cooling drum 2 preferably comprises one or more coolingelements or a cooling medium (not shown) that cools the cylindricalcooling surface 20 to accelerate the cooling of the continuous strip 9in a manner known per se.

The cooling apparatus 1 further comprises a guiding device 4 for guidingthe continuous strip 9 in a plurality of windings W1, W2, ..., Wn aroundthe cooling surface 20. As shown in FIG. 2 , each winding W1, W2, ...,Wn extends in an individual winding plane P1, P2, ..., Pn. Hence, thewindings W1, W2, ..., Wn are not helical, but can be considered as‘straight’ windings. In this example, said winding planes P1, P2, ...,Pn are mutually parallel yet spaced apart. More preferably, said windingplanes P1, P2, ..., Pn extend perpendicular or normal to the rotationaxis S. For clarity reasons, not all windings and planes have been givenan individual reference sign.

The guiding device 4 comprises first redirection or guiding elements 41and second redirection or guiding elements 42. The guiding device 4 isprovided with a guide frame 40 for supporting the guiding elements 41,42 in an angular position G, as shown in FIG. 3 , relative to thecooling drum 2. Preferably, said angular position G is at a stationaryangle F with respect to the rotation axis S. Hence, the cooling drum 2is rotatable about the rotation axis S relative to said guiding device4. The angular position G in this example is at approximately thirtydegrees with respect to the horizontal plane H, which is a position thatis easily reachable for an operator. The first guiding elements 41 arepreferably arranged side-by-side in the axial direction X, e.g. in alinear array. Similarly, the second guiding elements 42 are arrangedside-by-side in the axial direction X, e.g. in a linear array parallelto the linear array of the first guiding elements 41.

Each one of the first guiding elements 41 forms a set with one of thesecond guiding elements 42 to guide the continuous strip 9 in atransition from a first winding W1 to a consecutive winding W2 of theplurality of windings W1, W2, ..., Wn. Note that in the context of theclaims, the ‘first winding’ is not necessarily the very first winding,but the first winding of any pair of consecutive windings. The firstwinding where the continuous strip 9 is first applied to the coolingdrum 2 is hereafter referred to as the infeed winding W1. The lastwinding where the continuous strip 9 exits or leaves the cooling drum 2is hereafter referred to as the outfeed winding Wn.

As schematically shown in FIG. 8A, the first guiding element 41 of theset is arranged for receiving the continuous strip 9 from the firstwinding W1 in a first winding direction A and for directing thecontinuous strip 9 in a transition direction B towards the secondguiding element 42 of the set. The second guiding element 42 of the setis arranged for receiving the continuous strip 9 in the transitiondirection B from the first guiding element 41 of the set and fordirecting the continuous strip 9 into the consecutive winding W2 in asecond winding direction C. The transition direction B is different fromthe first winding direction A and the second winding direction C. Inparticular, the transition direction B extends obliquely with respect toboth the first winding direction A and the second winding direction C.In this particular example, the first winding direction A and the secondwinding direction C extend in the first winding plane P1 and the secondwinding plane P2, respectively. Consequently, as both winding planes P1,P2 in this example are parallel, the first winding direction A and thesecond winding direction C are also parallel.

As best seen in FIG. 3 , the first winding direction A and the secondwinding direction C are tangent to the cooling surface 20, meaning thatthey extend to or from the guiding elements 41, 42 along a line that istangent to the cooling surface 20. In this particular example, as shownin FIG. 1 and schematically in FIG. 8B, the first guiding elements 41are at a first distance M1 from the cooling surface 20 in the firstwinding direction A, wherein the first distance M1 is the same orsubstantially the same for all first guiding elements 41. Similarly, thesecond guiding elements 42 are at a second distance M2 from the coolingsurface 20 in the second winding direction C, wherein the seconddistance M2 is the same or substantially the same for all second guidingelements 42.

As shown in FIG. 8A, the second guiding elements 42 of each set areoffset with respect to the respective first guiding element 41 of thesame set in the axial direction X. In addition, the second guidingelements 42 of each set are offset with respect to the respective firstguiding element 41 of the same set in the circumferential direction D.The sum of the offsets in both directions defines the obliqueness of thetransition direction B. As shown in FIG. 3 , the first guiding element41 and the second guiding element 42 of each set are spaced apart in thecircumferential direction D over a spacing angle E in the range oftwenty to sixty degrees, and preferably in the range of thirty to fortydegrees. At such spacing angle E, the continuous strip 9 can be made totransition gradually, while the continuous strip 9 is still in contactwith the cooling surface 20 during a sufficient part of the remainingcircumference of the cooling drum 2. In this exemplary embodiment, asshown in FIG. 2 , the second guiding element 42 of each set is alignedin the circumferential direction D with the first guiding element 41 ofa consecutive one of the sets, i.e. the second guiding element 42 of oneset lies in the same winding plane P1, P2, ..., Pn as the first guidingelement 42 of a consecutive one of the sets.

As further shown in FIG. 3 , the first guiding element 41 and the secondguiding element 42 of each set define a linear transition path T for thecontinuous strip 9 to travel between the respective guiding elements 41,42. The first guiding element 41 and the second guiding element 42 ofeach set are preferably positioned relative to the cooling surface 20 sothat the transition path T is completely spaced apart from the coolingsurface 20. Hence, the transition of the continuous strip 9 can takeplace independently from the cooling surface 20 of the cooling drum 2.

As shown in more detail in FIGS. 4, 5, 6 and 7 , the first guidingelements 41 in this example are first guiding rollers 41. As shown inFIG. 6 , each first guiding roller 41 has an axis that defines a firstdeflection axis R1 for folding or deflecting the continuous strip 9 fromthe first winding direction A into the transition direction B. The firstdeflection axis R1 is tilted at an oblique first angle K1 to therotation axis S. Additionally or alternatively, said first deflectionaxis R1 extends in a direction perpendicular to both the first windingdirection A and the transition direction B. Said specific orientation ofthe first deflection axis R1 causes the first guiding roller 41 to twistthe continuous strip 9 in the part of the continuous strip 9 between thecooling surface 20 and the first guiding roller 41. In particular, oncethe continuous strip 9 arrives at the first guiding roller 41, it ispreferably in an orientation that is optimal for the subsequentdeflection of the continuous strip 9 about the first guiding roller 41from the first winding direction A into the transition direction B.

Similarly, the second guiding elements 42 in this example are secondguiding rollers 42. As shown in FIG. 7 , each second guiding roller 42has an axis that defines a second deflection axis R2 for folding ordeflecting the continuous strip 9 from the transition direction B intothe second winding direction C. The second deflection axis R2 is tiltedat an oblique second angle K2 to the rotation axis S, opposite to thefirst angle K1. Additionally or alternatively, said second deflectionaxis R2 extends in a direction perpendicular to both the second windingdirection C and the transition direction B. Said specific orientation ofthe second deflection axis R2 causes the first guiding roller 42 totwist the continuous strip 9 back with respect to the earlier twist atthe first guiding roller 41 in the part of the continuous strip 9between the cooling surface 20 and the second guiding roller 42. Inparticular, once the continuous strip 9 arrives at the second guidingroller 42, it is preferably in an orientation that is optimal for thesubsequent deflection of the continuous strip 9 about the second guidingroller 42 from the transition direction B into the second windingdirection C.

The guiding rollers 41, 42, due to their tilted orientation, are able totwist and subsequently merely deflect the continuous strip 9 around apart of their circumference. Consequently, the continuous strip 9 issubjected to a pure deflection without any substantial axial shifting orshear deformation. More in particular, its neutral line or theoreticalcenter line (not shown) is deflected around the guiding rollers 41, 42without any abrupt shifting in the axial direction X.

As shown in FIG. 7 , the guiding device 4 further comprises a pluralityof first alignment elements 51 for aligning the continuous strip 9 atone or more of the first guiding elements 41 along an entry line E1. Inthis exemplary embodiment, only two first alignment elements 51 areprovided at the first two windings W1, W2 to ensure proper feeding ofthe continuous strip 9 into the guiding device 4. It has been found thatfurther first alignment elements 51 can be dispensed with once thecontinuous strip 9 has been successfully fed into the guiding device 4over at least two windings W1, W2.

Optionally, the guiding device 4 may comprise one or more secondalignment elements 52 for aligning the continuous strip 9 at one or moreof the second guiding elements 42 along an exit line E2. In thisexemplary embodiment, second alignment elements 52 have been provided atall of the second guiding elements 42 to ensure that the windings W1,W2, ..., Wn are aligned at least once during each winding W1, W2, ...,Wn. Alternatively, the second alignment elements 52 may be provided at alimited number of second guiding elements 42.

Preferably, the alignment elements 51, 52 are alignment rollers 51, 52that can effectively align the continuous strip 9 as it passes whileconveying said continuous strip 9 with minimal friction.

As best seen in FIG. 7 , the alignment rollers 51, 52 are arranged at aslightly oblique angle relative to their respective guiding rollers 41,42 so that each combination of an alignment roller 51, 52 and a guidingroller 41, 42 forms a V-like configuration to guide and align thecontinuous strip 9. In particular, the guiding rollers 41, 42 arearranged for abutting the inside 90 of the continuous strip 9 while thealignment rollers 51, 52 have been provided at a slight angle to therespective guiding roller 41, 42 to obliquely abut the inside of thecontinuous strip 9 at or along the respective entry line E1 or exit lineE2.

Optionally, the angles K1, K2 may be adjustable, e.g. by adjustablymounting the rollers 41, 42 to the frame 40. As a further option, theframe 40 as a whole may be adjustable in position, e.g. in thecircumferential direction to adjust the angular position G or in theaxial direction X.

FIG. 10 shows a detail of an alternative cooling apparatus 101. The viewof FIG. 10 substantially corresponds to the view of FIG. 6 . Thealternative cooling apparatus 101 differs from the cooling apparatus 1of FIGS. 1-9 in that it features one or more alignment elements 151, 152at an intermediate position along the transition path T between thefirst guiding element 41 and the second guiding element 42 of each setfor steering the continuous strip 9 along the respective transition pathT. In this particular example, the one or more alignment elements 151,152 comprises a first alignment element 151 and a second alignmentelement 152 which are placed in close proximity to each other at saidintermediate position. The intermediate position as shown in more orless in the middle of the transition path T between the first guideelement 41 and the second guide element 42. However, it will be clearthat a different intermediate position, i.e. not in the middle of thetransition path T, is also possible. The alignment elements 151, 152 mayfor example be placed at ⅓ or ¼ of the transition path T.

In this exemplary embodiment, the one or more alignment elements 151,152 comprises a first alignment roller 151 and a second alignment roller152. Preferably, said first alignment roller 151 and said secondalignment roller 152 are oppositely inclined to abut the strip 9 fromdifferent or opposite sides.

FIGS. 11A and 11B show a production line 200 for producing thecontinuous strip 9. The production line 200 comprises an extruder 271for extruding the continuous strip 9 at a variable extrusion speed. Theproduction line 200 also comprises a further alternative coolingapparatus 201 according to a third exemplary embodiment of theinvention. The production line 200 additional has a buffer member 272between the extruder 271 and the further alternative cooling apparatus201 to absorb variations in the extrusion speed. The buffer member 272may be a dancer roller or sensor unit to control the length of a freeloop 99 in the continuous strip 9 in response to variations in theextrusion speed. The production line 200 also features a control unit Uthat is operationally and/or electronically connected to one or more ofthe extruder 271, the buffer member 272 and the further alternativecooling apparatus 201 in a manner that will be described hereafter.

The further alternative cooling apparatus 201 may have substantially thesame features as the previously discussed cooling apparatuses 1, 101.However, for this embodiment, the guide elements and/or the alignmentelements are not essential. The differentiating features of thisembodiment can for example also be applied independently of the previousembodiments, i.e. in combination with the prior art cooling apparatus ofFIG. 13 . Basically, the further alternative cooling apparatus 201 onlyrequires a cooling drum 2 that is driven or drivable at a rotationalspeed V1. The control unit U is operationally and/or electronicallyconnected to a drum drive or motor 273 of the cooling drum 2 to controlsaid rotational speed V1.

The further alternative cooling apparatus 201 differs from thepreviously discussed cooling apparatuses 1, 101 and the prior artcooling apparatus in that it has a infeed pulling member 281 that islocated between the buffer member 272 and the cooling drum 2 for feedingthe continuous strip 9 into the infeed winding W1 at an infeed speed V2.The control unit U is operationally and/or electronically connected tothe infeed pulling member 281 and configured to control the infeedpulling member 281 such that the infeed speed V2 is lower than therotational speed V1 of the cooling drum 2. The infeed speed V2 may forexample be at least five percent or at least ten percent lower than therotation speed V1. Hence, the continuous strip 9, which is still warmand flexible during the infeed winding W1, can be slightly pulled backto reduce or prevent sagging or slacking. In particular, the slight pullon the continuous strip 9 can ensure that the infeed winding W1 istightly wound around the cooling drum 2, thereby improving theeffectiveness of said cooling drum 2.

Because of the speed difference between the infeed speed V2 and therotational speed V1 of the cooling drum 2, the continuous strip 9 may bestretched slightly. Optionally, the infeed speed V2 can be variablecontrolled to control the stretching and therefore the dimension, i.e.the cross section, height and/or width, of the continuous strip 9.

Additionally, or alternative, an outfeed pulling member 282 may beprovided for feeding the continuous strip 9 out of the outfeed windingWn away from the cooling drum 2. The control unit U is operationallyand/or electronically connected to the outfeed pulling member 282 andconfigured to control the outfeed pulling member 282 such that it pullson the continuous strip 9 at an outfeed speed V3 that is higher than therotational speed V2 of the cooling drum 2. The outfeed speed V3 may forexample be at least five percent or at least ten percent higher than therotation speed V1. At the outfeed winding Wn, the continuous strip 9 isalready partially cooled and relatively inflexible. By pulling thecontinuous strip 9 forward out of outfeed winding Wn, it can beprevented that the continuous strip 9 leaves the outfeed winding Wnunintentionally.

Preferably, the infeed pulling member 281 comprises one or more pullingrollers 283, in this exemplary embodiment a set of two pulling rollers283. At least one of the pulling rollers 283 is actively driven andcontrolled by the control unit U to rotate at the outfeed speed V3.Similarly, the outfeed pulling member 282 preferably comprises one ormore pulling rollers 284, in this exemplary embodiment a set of twopulling rollers 284, at least one of which is actively driven andcontrolled by the control unit U.

The pulling rollers 283 of the infeed pulling member 281 may berelatively smooth to ensure optimal grip between the warm, tackycontinuous strip 9 and the pulling roller 283. In contrast, the pullingrollers 284 of the outfeed pulling member 282 may be relatively rough togenerate an appropriate amount of grip between the at least partiallycooled continuous strip 9 and the pulling rollers 284 while alsoallowing for slip between the continuous strip 9 and the pulling rollers284. In particular, slack in the continuous strip 9 between the coolingdrum 2 and the outfeed pulling member 282 will be pulled tight by thepulling rollers 284 of the outfeed pulling member 282, but as soon asthe slack is removed, the at least partially cooled continuous strip 9can no longer match the higher outfeed speed V3 of outfeed pullingmember 282 and - as a result - will slip over the surface of the pullingrollers 284.

FIG. 12 shows a further alternative cooling apparatus 301 according to afourth embodiment of the invention that differs from the previouslydiscussed cooling apparatuses 1, 101, 201 in that its guiding device 304comprises a third redirection or guiding element 343 between the firstguiding element 41 and the second guiding element 42 of each set. Thethird guiding element 304 is arranged for twisting and/or deflecting thecontinuous strip 9 in a similar way as the first guiding element 41 andthe second guiding element 42 about a third deflection axis R3. Becauseof the presence of the third guiding element 304, the twist ordeflection of the continuous strip 9 at the first guiding element 41and/or the second guiding element 42 can be slightly reduced to preventaxial shifting or shear deformation. In particular, the continuous strip9 can initially be directed from the first winding direction A into afirst transition direction B1 different from said first windingdirection A. The continuous strip 9 can subsequently be received at thethird guiding element 343 in the first transition direction B1 anddirected further into a second transition direction B2 different fromthe first transition direction B1 towards the second guiding element 42.Ultimately, the continuous strip 9 can be received at the second guidingelement 42 in the second transition direction B2. It is noted theaverage of the first transition direction B1 and the second transitiondirection B2 still results in the same overall transition direction asin the previously discussed embodiments.

It will be apparent to one skilled in the art that the guiding device304 may comprise a plurality of third or further guiding elementsbetween the first guiding element 41 and the second guiding element 42of each set to divide the transition path in even more sections, eachwith its own transition direction. As a group, the plurality of third orfurther guiding elements 343 are arranged for receiving the continuousstrip 9 in the first transition direction B1 from the first guidingelement 41 and for directing said continuous strip 9 towards the secondguiding element 42 in the second transition direction B2 in a similarway as the single third guiding element 343.

The method for cooling the continuous strip 9 with the use of theaforementioned cooling apparatuses 1, 101, 201 will now be describedwith reference to FIGS. 1-11 .

As shown in FIG. 3 , the freshly extruded, continuous strip 9 issupplied from an extruder (not shown) to the cooling drum 3. Preferable,an infeed member 61, such as a dancer roller, is provided to guide theinfeed winding W1 to the cooling surface 20 of the cooling drum 2. Inthis example, the continuous strip 9 is fed to the cooling drum 2 frombelow. As shown in FIG. 9A, this means that the infeed winding W1extends over approximately a quarter of the circumference of the coolingsurface 20 in the circumferential direction D prior to receiving of thecontinuous strip 9 at the first of the first guiding elements 41.Alternatively, as shown in dashed lines in FIG. 9A, the continuous strip9 may be fed to the cooling drum 2 from an alternative infeed member 62above the cooling drum 2, so that the infeed winding W1 extends over aconsiderably longer portion of the circumference of the cooling drum 2,e.g. at least three quarters. Hence, the cooling effectiveness of thecooling drum 2 can be increased.

When approaching the first guiding element 41 of one of the sets, thecontinuous strip 9 leaves the cooling surface 20 and extends in thefirst winding direction A and in the first winding plane P1 towards thefirst guiding element 41. Between the cooling surface 20 and the firstguiding element 41, the continuous strip 9 is twisted as discussedbefore. Once the continuous strip 9 reaches the first guiding element 41of one of the sets, it is received by said first guiding element 41 inthe first winding direction A and subsequently directed by said firstguiding element 41 in the transition direction B towards the secondguiding element 42 of the same set. The continuous strip 9 subsequentlytravels along the transition path T as shown in FIG. 3 from the firstguiding element 41 towards the second guiding element 42. Because of thedifference in orientation of the two roller axes R1, R2, the continuousstrip 9 is twisted slightly between the two guiding elements 41, 42 ofthe set in order to position the continuous strip 9 optimally for thesubsequent deflection at the second guiding element 42. The continuousstrip 9 is then received by the second guiding element 42 in thetransition direction B and directed by said second guiding element 42from the transition direction B into the second winding direction C andinto the second winding plane P2. The continuous strip 9 is allowed totwist back into an orientation in which the inside 90 is parallel againto the rotation axis S. The continuous strip 9 contacts the coolingsurface 20 again and subsequently enters the second winding W2.

The above process is repeated at the transition between each winding W1,W2, ..., Wn until the outfeed winding Wn has been reached. At one ormore of the windings W1, W2, ..., Wn, the method comprises the step ofaligning the continuous strip 9 along the entry line E1 and/or the exitline E2 as previously discussed.

As shown in FIG. 9B, the outfeed winding Wn preferably extends over atleast a quarter up to at least three quarters of the circumference ofthe cooling surface 20 in the circumferential direction D after thecontinuous strip 9 has left the last of the second guiding elements 42.Hence, the coolest part of the cooling drum 2 can be used effectively.

At startup, the continuous strip 9 is guided manually through or alongeach of the guiding elements 41, 42. Once the outfeed winding Wn hasbeen connected to a downstream station, the continuous strip 9 can bepulled through automatically. When feeding the leading end of thecontinuous strip 9 through each winding W1, W2, ..., Wn at the startup,tools may be used to temporarily clamp the continuous strip 9 to thecooling drum 2, e.g. through magnetic attraction.

It is to be understood that the above description is included toillustrate the operation of the preferred embodiments and is not meantto limit the scope of the invention. From the above discussion, manyvariations will be apparent to one skilled in the art that would yet beencompassed by the scope of the present invention.

1. A cooling apparatus for cooling a continuous strip, wherein the cooling apparatus comprises a cooling drum with a cylindrical cooling surface that extends in a circumferential direction and has a rotation axis concentric to the cooling surface and extending in an axial direction, wherein the cooling drum is arranged for receiving the continuous strip in a plurality of windings around the cooling surface, wherein the plurality of windings comprises an outfeed winding where the continuous strip ultimately leaves the cooling drum, wherein the cooling apparatus further comprises an outfeed pulling member for feeding the continuous strip out of the outfeed winding away from the cooling drum, wherein the cooling apparatus further comprises a control unit that is operationally connected to the cooling drum to control the rotational speed of said cooling drum, wherein the control unit is operationally connected to the outfeed pulling member and configured to control the outfeed pulling member such that it pulls on the continuous strip at an outfeed rate that is higher than the rotational speed of the cooling drum.
 2. The cooling apparatus according to claim 1, wherein the outfeed speed is at least five percent or at least ten percent higher than the rotational speed of the cooling drum.
 3. The cooling apparatus according to claim 1, wherein the cooling apparatus further comprises a guiding device with a plurality of guiding elements for guiding the continuous strip in the plurality of windings around the cooling surface.
 4. The cooling apparatus according to claim 3, wherein the outfeed winding extends over at least a quarter up to at least three quarters of the circumference of the cooling surface in the circumferential direction after the continuous strip has left the last of the guiding elements.
 5. The cooling apparatus according to claim 1, wherein the plurality of windings comprises an infeed winding where the continuous strip is first applied to the cooling drum, wherein the cooling apparatus comprises an infeed pulling member for feeding the continuous strip into the infeed winding at an infeed speed, wherein the control unit is operationally connected to the infeed pulling member and configured to control the infeed pulling member such that the infeed speed is lower than the rotational speed of the cooling drum.
 6. A production line for producing a continuous strip, wherein the production line comprises an extruder for extruding the continuous strip at a variable extrusion speed, a cooling apparatus according to claim 1 for cooling the continuous strip and a buffer member between the extruder and the cooling apparatus to absorb variations in the extrusion speed, wherein the production line further comprises a control unit that is operationally connected to the cooling drum to control the rotational speed of said cooling drum, wherein the control unit is operationally connected to the outfeed pulling member and configured to control the outfeed pulling member such that it pulls on the continuous strip at an outfeed speed that is higher than the rotational speed of the cooling drum.
 7. The production line according to claim 6, wherein the plurality of windings comprises an infeed winding where the continuous strip is first applied to the cooling drum, wherein the cooling apparatus comprises an infeed pulling member that is located between the buffer member and the cooling drum for feeding the continuous strip into the infeed winding at an infeed speed, wherein the control unit is operationally connected to the infeed pulling member and configured to control the infeed pulling member such that the infeed speed is lower than the rotational speed of the cooling drum.
 8. A method for cooling a continuous strip using the cooling apparatus according to claim 1, wherein the method comprises receiving the continuous strip in a plurality of windings around the cooling surface, wherein the plurality of windings comprises an outfeed winding where the continuous strip ultimately leaves the cooling drum, wherein the method further comprises the step of pulling on the continuous strip that leaves the outfeed winding at an outfeed speed that is higher than the rotational speed of the cooling drum.
 9. The method according to claim 8, wherein the plurality of windings comprises an infeed winding where the continuous strip is first applied to the cooling drum, wherein the method comprises the step of feeding the continuous strip into the infeed winding at an infeed speed that is lower than the rotational speed of the cooling drum.
 10. The method according to claim 9, wherein the method further comprises the step of winding the outfeed winding over at least a quarter up to at least three quarters of the circumference of the cooling surface in the circumferential direction after the continuous strip has left the last of the guiding elements.
 11. A cooling apparatus for cooling a continuous strip, wherein the cooling apparatus comprises a cooling drum with a cylindrical cooling surface that extends in a circumferential direction and has a rotation axis concentric to the cooling surface and extending in an axial direction, wherein the cooling drum is arranged for receiving the continuous strip in a plurality of windings around the cooling surface, wherein the plurality of windings comprises an infeed winding where the continuous strip is first applied to the cooling drum, wherein the cooling apparatus comprises an infeed pulling member for feeding the continuous strip into the infeed winding at an infeed speed, wherein the cooling apparatus further comprises a control unit that is operationally connected to the cooling drum to control the rotational speed of said cooling drum, wherein the control unit is operationally connected to the infeed pulling member and configured to control the infeed pulling member such that the infeed speed is lower than the rotational speed of the cooling drum.
 12. The cooling apparatus according to claim 11, wherein the infeed speed is at least five percent or at least ten percent lower than the rotation speed.
 13. The cooling apparatus according to claim 11, wherein the cooling apparatus further comprises a guiding device with a plurality of guiding elements for guiding the continuous strip in the plurality of windings around the cooling surface.
 14. The cooling apparatus according to claim 13, wherein the infeed winding extends over at least a quarter up to at least three quarters of the circumference of the cooling surface in the circumferential direction prior to receiving the continuous strip at the first of the guiding elements.
 15. The cooling apparatus according to claim 11, wherein the continuous strip is fed to the cooling apparatus from below.
 16. The cooling apparatus according to claim 11, wherein the continuous strip is fed to the cooling apparatus from above.
 17. A production line for producing a continuous strip, wherein the production line comprises an extruder for extruding the continuous strip at a variable extrusion speed, a cooling apparatus according to claim 11 for cooling the continuous strip and a buffer member between the extruder and the cooling apparatus to absorb variations in the extrusion speed, wherein the production line further comprises a control unit that is operationally connected to the cooling drum to control the rotational speed of said cooling drum, wherein the control unit is operationally connected to the infeed pulling member and configured to control the infeed pulling member such that the infeed speed is lower than the rotational speed of the cooling drum.
 18. A method for cooling a continuous strip using the cooling apparatus according to claim 11, wherein the method comprises receiving the continuous strip in a plurality of windings around the cooling surface, the plurality of windings comprises an infeed winding where the continuous strip is first applied to the cooling drum, wherein the method comprises the step of feeding the continuous strip into the infeed winding at an infeed speed that is lower than the rotational speed of the cooling drum.
 19. Method according to claim 16, wherein the method further comprises the step of winding the infeed winding over at least a quarter up to at least three quarters of the circumference of the cooling surface in the circumferential direction prior to receiving the continuous strip at the first of the guiding elements. 